@media only screen and (min-width: 840px) and (max-width: 1070px) {
    /*中间图片*/
    .pic li {
        width: 50% !important;
    }
    .pic li:nth-child(1) {
        background: url(../img/mid-pic/whereisthelove_medium.jpg) center;
    }
    .pic li:nth-child(2) {
        background: url(../img/mid-pic/swift_playground_medium.jpg) center;
    }
    .pic li:nth-child(3) {
        background: url(../img/mid-pic/accessories_medium.jpg) center;
    }
    .pic li:nth-child(4) {
        background: url(../img/mid-pic/event_teaser_medium.jpg) center;
    }

    /*footer*/
    footer .site {
        display: block;
    }
}
